1. Field
The invention relates to an inductive component having at least one winding and a soft magnetic core made of a ferromagnetic material. In particular, the invention relates to inductive components having a soft magnetic core made of a powder composite.
2. Description of Related Art
Certain soft magnetic powder composites in the form of molded magnetic cores have been known for some time.
For one, molded powder composites made of powdered iron are known. By use of these magnetic cores, the permeability range is well covered from approximately 10 to 300. Saturation inductions of approximately 1.6 Tesla can be achieved with these magnetic cores. The application frequencies are typically below 50 kHz on account of the comparatively low specific resistance and the size of the iron particles.
In addition, molded powder composites made of soft magnetic crystalline iron-aluminum-silicon alloys are known. Using these powder composites, application frequencies of greater than 100 kHz can be achieved due to the comparatively higher specific resistance.
Particularly good saturation inductions and permeabilities can be achieved using powder composites based on crystalline nickel-iron alloys. Permeabilities ranging up to approximately 500 can be realized by precise adjustment of the nickel content. Using these powder composites, application frequencies of greater than 100 kHz are likewise possible because of the comparatively low magnetic reversal losses.
However, these three known powder composites can be processed only into molds having very simple geometric shapes, since the molding technologies currently available allow for only a limited scope. In particular, only annular cores and/or pot cores can be manufactured.
To avoid these disadvantages, it is known from DE 198 46 781 A1, for example, to process soft magnetic alloy powders using injection molding methods to produce ferromagnetic powder composites. In this regard, nanocrystalline alloys in particular are incorporated into an injection-moldable plastic, in particular a polyamide, and subsequently injection-molded to produce soft magnetic cores.
In addition, it is known to the applicant to cast nanocrystalline alloys with cast resins to produce ferromagnetic powder composites.